I can barely believe my figures! I was trying to calculate how the last five days of rain at Sacramento Executive Airport (Jan. 7-11, 2017: 5.58 inches) compared to other rainy 5-day periods in the past. So I downloaded a ton of met data from 1980-2016 (37 years of data, including years known with epic rains, like 1982 and 1986) and assembled a giant spreadsheet.
It turns out the last five days are Number One on the list, easily beating out second place, Feb. 13-17, 1986: 5.28 inches).
Well, that explains a lot!
This link provides more information about the storm of 1986. That stormy period was epic, but in higher terrain. Being in the Valley, Sacramento Executive Airport missed the heaviest of those rains, having only three heavy rain days that did not match our recent bout of rainfall. A fluke, but a legitimate one.